Here's a racist joke but it runs in the other direction:

Two black guys are at the County Fair and they are exploring the little side show tents. They spot a tent with a sign that says "Turn You White $15".

They think about for a minute and then decide that might be great, if it works. So they look in their wallets and one guy has a $10 bill and the other has a $20. So the guy with $10 says: "You go ahead and then if it works I'll take the $5 change and take my turn."

The first one is in the tent for quite a while, but finally comes out. He's the perfect image of a white man: Blond hair, blue eyes, and he even has a new suit! The other guy says: "That's amazing! Quick give me the $5 so I can go in."

The white man turns to him and says: "Screw you! Get a job!"